tox: Update pytest-mock to 0.10.1.

- Fix regression in frozen tests due to distutils import dependency.
- Fix regression when using pytest-mock with pytest-2.7.X.

tox.ini

@@ -32,7 +32,7 @@ deps =
     pytest-cov==2.2.0
     pytest-faulthandler==1.3.0
     pytest-html==1.7
-    pytest-mock==0.10.0
+    pytest-mock==0.10.1
     pytest-qt==1.11.0
     pytest-instafail==0.3.0
     pytest-travis-fold==1.2.0